1. Field of the Invention
The present invention relates to an optical device and a method for manufacturing such an optical device.
2. Description of the Related Art
Among optical devices, there is an optical device as shown in FIG. 8. In this optical device, an end face 2 of a bare fiber 1 inserted into and secured to a ferrule 4 is protruded outwardly from an end face 5 of the ferrule 4, and an anti-reflection film or other film 3 is coated on the protruded end face 2 of the bare fiber 1.
A optical device as shown in FIG. 8 is manufactured in the following manner. A metal film is formed on a side surface 12 of one longitudinal end portion of the bare fiber 1. Then, the bare fiber 1 having the side surface 12 on which the metal film was formed is inserted into the ferrule 4 so that the end face 2 of the bare fiber 1 is protruded outwardly from the end face 5 of the ferrule 4. Thereafter, the bare fiber 1 inserted in the ferrule 4 is secured to the ferrule 4 by soldering up to the side surface 12 on which the metal film was formed. Then, the bare fiber 1 with the ferrule 4 is set in a vacuum chamber of a film forming device, where an anti-reflection film or other film 1 is formed on the end face 2 of the bare fiber 1 protruded from the end face 5 of the ferrule 4 by depositing evaporation atoms or molecules of film forming material.
In an optical device manufacturing method according to the present invention, a metal film is formed on a side surface of a bare fiber and a film is formed on an end face of the bare fiber, and, thereafter, the bare fiber is inserted into a ferrule in such a manner that the end face on which the film was formed is protruded from an end face of the ferrule, and the bare fiber is secured to the ferrule.
In an optical device according to the present invention, in which a bare fiber having a side surface on which a metal film was formed is inserted into and secured to a ferrule, an end face of the bare fiber is protruded outwardly from an end face of the ferrule, and, when it is assumed that a distance between the end faces is L and an outer diameter of the bare fiber having the side surface on which the metal film was formed is d, a relationship L less than 4xc3x97d is satisfied, and a film is formed on the end face of the bare fiber.